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SubjectRe: [PATCH] hwmon: (ibmaem) Replace zero-length array with flexible-array member
On Tue, Feb 11, 2020 at 05:42:37PM -0600, Gustavo A. R. Silva wrote:
> The current codebase makes use of the zero-length array language
> extension to the C90 standard, but the preferred mechanism to declare
> variable-length types such as these ones is a flexible array member[1][2],
> introduced in C99:
>
> struct foo {
> int stuff;
> struct boo array[];
> };
>
> By making use of the mechanism above, we will get a compiler warning
> in case the flexible array does not occur last in the structure, which
> will help us prevent some kind of undefined behavior bugs from being
> inadvertenly introduced[3] to the codebase from now on.
>
> This issue was found with the help of Coccinelle.
>
> [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
> [2] https://github.com/KSPP/linux/issues/21
> [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Applied to hwmon-next.

Thanks,
Guenter

> ---
> drivers/hwmon/ibmaem.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/hwmon/ibmaem.c b/drivers/hwmon/ibmaem.c
> index db63c1295cb2..fb052c2d9c34 100644
> --- a/drivers/hwmon/ibmaem.c
> +++ b/drivers/hwmon/ibmaem.c
> @@ -232,7 +232,7 @@ struct aem_read_sensor_req {
>
> struct aem_read_sensor_resp {
> struct aem_iana_id id;
> - u8 bytes[0];
> + u8 bytes[];
> } __packed;
>
> /* Data structures to talk to the IPMI layer */

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